The rising levels of atmospheric CO2 concentrations will have a detrimental effect on global crops which supply a large portion of worldwide populations.

According to a new study conducted at the Harvard School of Public Health (HSPH), dietary iron and zinc concentrations found in crops will have been significantly reduced by the year 2050.

Considering the fact that a reported two billion people across the globe are iron- and zinc-deficient, the decline in the concentration of these important nutrients poses a significant threat to human life.

Lead study author Samuel Myers, research scientist in the Department of Environmental Health at HSPH, sought to determine whether or not the steady increase of CO2 concentration would threaten human nutrition due to the effects it has on crops.

The researchers found a significant decrease in the concentrations of iron, zinc, and protein in C3 grains. They estimate that approximately two to three billion people around the world get 70 percent or more of their dietary iron and/or zinc from C3 crops. With people in the developing world already being zinc- and iron-deficient, this already-present health concern is expected to become much more severe in the coming decades.

“Humanity is conducting a global experiment by rapidly altering the environmental conditions on the only habitable planet we know. As this experiment unfolds, there will undoubtedly be many surprises. Finding out that rising CO2 threatens human nutrition is one such surprise,” said Myers in a statement.

The findings of the study are published online in Nature.